Tank trailers are used to transport fuels and other fluids from one location to another location. Some tank trailers are little more than a tank with wheels and a trailer hitch, which provides no means for secondary containment of a fuel or other fluid leaking or spilling from the tank. One potential approach to this problem is to use a double-walled tank in which an interior wall defines a volume for the tank and an exterior wall surrounds the interior wall. The void between the surfaces of the interior and exterior walls provides a secondary containment region for any fluid leaking through the interior wall. However, double-walled tanks are significantly more expensive to construct than single walled tanks. In addition, it can be difficult to detect leakage through the interior wall, particularly at the initial stages of a leakage problem if only a small amount of fluid is escaping through the interior wall. Some double-walled tanks attempt to address this problem by installing a sight glass or access port into the secondary containment region between the tank walls. Nonetheless, it is advantageous to be able to visually inspect as much of the exterior surface of the interior wall as possible so that leakage problems can be detected as soon as possible.
The prior art in this field includes the following:
InventorPatent No.Issue DateErickson6,715,195Apr. 6, 2004Page5,232,246Aug. 3, 1993Marino5,071,166Dec. 10, 1991Morris4,482,017Nov. 13, 1984Kerr3,604,719Sep. 14, 1971Dascanio3,352,461Nov. 14, 1967Kachnik3,263,865Aug. 2, 1966Brehany et al.2,567,164Sep. 11, 1951Taylor2,421,765Jun. 10, 1947
None of the prior art references disclosed above appear to show a tank trailer having a tank surrounded by an open secondary containment region. This approach combines the advantages of a secondary containment system with a convenient of means for visually inspecting the tank for leaks.